Computer-readable storage medium storing information processing program, information processing device, information processing system, and information processing method

ABSTRACT

An example game device corrects a sound of a sound source located behind a virtual camera by applying a frequency filter to the sound. Specifically, an angle between an imaging direction of the virtual camera and a direction from the virtual camera toward the sound source is calculated. If the absolute value of the angle is 90 degrees or more, a filter value is calculated based on the angle. The game device also corrects the filter value based on a distance between the virtual camera and the sound source. The game device applies a low-pass filter corresponding to the filter value to the sound of the sound source.

CROSS REFERENCE TO RELATED APPLICATION

The disclosure of Japanese Patent Application No. 2011-247127, filedNov. 11, 2011, is incorporated herein by reference.

FIELD

The technology disclosed herein relates to information processingprograms, information processing devices, information processingsystems, and information processing methods for controlling sounds.

BACKGROUND AND SUMMARY

Conventionally, an object (sound source) is displayed so that it appearsto be provided in a virtual three-dimensional space and generate asound. To do so, a process is executed so that the sound is heard from adirection in which the object is located.

However, in conventional techniques, for example, in a situation thatthere are a plurality of sound sources located in different directions,there is room for improvement with regard to distinguishing betweensounds of the sound sources.

Therefore, it is an object of an exemplary embodiment to provide aninformation processing program, information processing device,information processing system, and information processing method whichcan distinguishing between sounds of sound sources located in differentdirections.

In order to achieve the object, exemplary embodiments haveconfigurations as follows.

An exemplary embodiment is a computer-readable storage medium storing aninformation processing program executable by a computer of aninformation processing device for generating an image of a virtual spacecaptured by a virtual camera and outputting a sound of a sound sourceprovided in the virtual space. The program causes the computer toexecute calculating a direction of the sound source as viewed from thevirtual camera or a predetermined character provided in the virtualspace, correcting the sound of the sound source by applying apredetermined filter to the sound when the sound source is located in apredetermined direction, and outputting the corrected sound.

With this configuration, when the sound source is located in apredetermined direction as viewed from the virtual camera (e.g., behindthe virtual camera, to the right of the virtual camera, etc.), apredetermined filter is applied to the sound of the sound source. Forexample, when the sound source is located behind the virtual camera, afrequency filter may be applied to the sound of the sound source so thatthe sound becomes muffled.

In another configuration, an angle between an imaging direction of thevirtual camera or a direction measured with reference to thepredetermined character and the direction of the sound source may becalculated.

With this configuration, for example, an angle between the imagingdirection of the virtual camera and the direction of the sound source iscalculated.

In another configuration, when the calculated angle is greater than afirst threshold value, the sound may be corrected.

With this configuration, when the calculated angle is greater than apredetermined threshold value, the sound is corrected.

In another configuration, a degree of correction of the sound may beincreased with an increase in the calculated angle.

With this configuration, the degree of correction of the sound isincreased with an increase in the angle.

In another configuration, when the sound source is located behind thevirtual camera or the predetermined character, the sound may becorrected.

With this configuration, when the sound source is located behind thevirtual camera or the predetermined character, the sound is corrected.

In another configuration, the sound may also be corrected based on adistance between the virtual camera or the predetermined character andthe sound source.

With this configuration, the sound is additionally corrected based onthe distance between the virtual camera or the predetermined characterand the sound source.

In another configuration, when the distance between the virtual cameraor the predetermined character and the sound source is larger than asecond threshold value, the sound may be corrected.

With this configuration, when the distance between the virtual cameraand the sound source is larger than the second threshold value, thesound is corrected. Specifically, a sound of a sound source located inthe vicinity of the virtual camera is not corrected, while a sound of asound source located the second threshold value away from the virtualcamera is corrected.

In another configuration, a degree of correction of the sound may beincreased with an increase in the distance.

With this configuration, the degree of correction is increased with anincrease in the distance.

In another configuration, a maximum value of a degree of correction maybe set based on the angle. The degree of correction may be determinedwithin the maximum value based on a distance between the virtual cameraor the predetermined character and the sound source, and the sound maybe corrected based on the degree of correction.

With this configuration, the maximum value of the degree of correctionis set based on the angle. The degree of correction is determined withinthe maximum value based on the distance.

In another configuration, the degree of correction of the sound may beincreased by increasing a degree of attenuation of a volume of apredetermined frequency component of the sound.

With this configuration, the degree of correction is increased byincreasing the degree of attenuation of a predetermined frequencycomponent.

In another configuration, the sound may be corrected by attenuating apredetermined frequency component of the sound.

With this configuration, the sound is corrected by attenuating apredetermined frequency component.

In another configuration, the program may cause the computer to furtherexecute determining whether or not to correct the sound, based on thetype of the sound source or the type of the sound of the sound source.When it is determined that the sound is to be corrected, the sound iscorrected.

With this configuration, it is determined whether or not the sound is tobe corrected, based on the type of the sound source or the type of thesound of the sound source.

In another configuration, a degree of correction of the sound may be setbased on the type of the sound source or the type of the sound of thesound source, and the sound may be corrected to the degree ofcorrection.

With this configuration, the degree of correction is set based on thetype of the sound source or the type of the sound of the sound source.

In another configuration, the predetermined filter may be a frequencyfilter.

With this configuration, the sound is easily corrected using a frequencyfilter.

In another configuration, the frequency filter may be at least one of alow-pass filter and a band-pass filter.

With this configuration, at least one of a low-pass filter and aband-pass filter is used as the frequency filter.

An exemplary embodiment may be an information processing device(information processing system) for executing the above informationprocessing program. The information processing system may include asingle device or a plurality of devices which operate in cooperationwith each other. An exemplary embodiment may be an informationprocessing method executable in the information processing system.

According to an exemplary embodiment, it is possible to distinguishbetween sounds of sound sources located in different directions.

These and other objects, features, aspects and advantages of theexemplary embodiments will become more apparent from the followingdetailed description of the exemplary embodiments when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example non-limiting block diagram showing a configurationof a game system 1;

FIG. 2 is an example non-limiting diagram showing video (image) which isdisplayed on a television 2 when a game of this embodiment is executed;

FIG. 3 is an example non-limiting diagram showing each object in a gamespace as viewed from above, indicating a location relationship betweeneach object in the game space;

FIG. 4 is an example non-limiting diagram showing another example video(image) displayed on the television 2 when the game of this embodimentis executed;

FIG. 5 is an example non-limiting diagram showing each object in thegame space as viewed from above when the image of FIG. 4 is displayed,indicating a location relationship between each object provided in thegame space;

FIG. 6 is an example non-limiting diagram showing the volume of a soundof a sound source 53 which is determined based on a distance between avolume calculation microphone 62 and a sound source 53;

FIG. 7 is an example non-limiting diagram showing determination(left-right localization) of a localized position in a left-rightdirection (left-right position) of the sound source 53;

FIG. 8 is an example non-limiting diagram showing determination(front-back localization) of a localized position in a front-backdirection (front-back position) of the sound source 53;

FIG. 9 is an example non-limiting diagram showing the left-rightposition, front-back position, and volume of the sound source 53 when alocalization calculation microphone 61, the volume calculationmicrophone 62, and the sound source 53 have a predetermined locationrelationship;

FIG. 10 is an example non-limiting diagram showing a movement of anarrow object (sound source 54) toward a virtual camera 60 in the gamespace as viewed from above;

FIG. 11 is an example non-limiting diagram showing each object in thegame space as viewed from above, where a sound source 52 is locatedbehind the virtual camera 60;

FIG. 12 is an example non-limiting diagram showing a filter value basedon a location relationship between a back filter microphone 64 and thesound source 52;

FIG. 13 is an example non-limiting diagram showing frequency filtering,where different filter values are used;

FIG. 14 is an example non-limiting diagram showing various data itemsused in a game process;

FIG. 15 is an example non-limiting main flowchart showing a flow of thegame process executed in the game device 3;

FIG. 16 is an example non-limiting flowchart showing a detailed flow ofa localization/volume calculation process (step S4) of FIG. 15; and

FIG. 17 is an example non-limiting flowchart showing a detailed flow ofa filtering process (step S5) of FIG. 15.

DETAILED DESCRIPTION OF NON-LIMITING EXAMPLE EMBODIMENTS

[1. General Configuration of Game System]

A game system 1 according to an exemplary embodiment will be describedhereinafter with reference to the accompanying drawings. FIG. 1 is anexample non-limiting block diagram showing a configuration of the gamesystem 1. In FIG. 1, the game system 1 includes a display device (e.g.,a television receiver (hereinafter referred to as a “television”)) 2, agame device 3, an optical disc 4, and a controller 5. In the game system1, a game process is performed by the game device 3 based on a gameoperation performed using the controller 5, and a game image obtainedthrough the game process is displayed on the television 2.

In the game device 3, the optical disc 4 typifying an interchangeableinformation storage medium used for the game device 3 is removablyinserted. An information processing program (typically, a game program)to be executed by the game device 3 is stored on the optical disc 4.

The television 2 is connected to the game device 3 by a connecting cord.A game image obtained as a result of a game process performed by thegame device 3 is displayed on the television 2. The television 2includes a loudspeaker 2 a which outputs a game sound obtained as aresult of the game process. In alternative embodiments, the loudspeaker2 a may be separated from the television 2. The game sound may be outputfrom a monaural loudspeaker or a stereo loudspeaker. Alternatively, thegame sound may be output from a 5.1 channel surround sound loudspeaker.

The controller 5 provides the game device 3 with operation data producedbased on an operation performed on the controller itself. The controller5 and the game device 3 can communicate with each other via wireless (orwired) communication. While only one controller is included in the gamesystem 1 in FIG. 1, a plurality of the controllers 5 may be included inthe game system 1.

The controller 5 has a plurality of operation buttons (e.g., a crossbutton for selecting a direction, a plurality of push buttons, etc.).Information about an operation on the operation buttons performed by auser is transmitted as operation data from the controller 5 to the gamedevice 3.

The game device 3 includes a CPU 10, a system LSI 11, an external mainmemory 12, a disc drive 14, an AV-IC 15, etc.

The CPU 10 performs a game process by executing the above game program,and functions as a game processor. The CPU 10 is connected to the systemLSI 11. In addition to the CPU 10, the external main memory 12, the discdrive 14, and the AV-IC 15 are connected to the system LSI 11. Thesystem LSI 11 performs the following processes: controlling datatransfer between each component connected thereto; generating an imageto be displayed; acquiring data from an external device(s); and thelike. The external main memory 12, which is of a volatile type, stores agame program read from the optical disc 4 and various kinds of data. Theexternal main memory 12 is used as a work area and a buffer area for theCPU 10. The disc drive 14 reads program data, audio data, etc. from theoptical disc 4, and writes the read data into an internal main memory 11d or the external main memory 12.

The system LSI 11 includes a graphics processor unit (GPU) 11 a, adigital signal processor (DSP) 11 b, a video RAM (VRAM) 11 c, and theinternal main memory 11 d. Although not shown in the figures, thesecomponents 11 a to 11 d are connected to each other by an internal bus.

The GPU 11 a, which forms a part of a drawing or rendering mechanism,generates an image in accordance with a graphics command (drawing orrendering command) from the CPU 10. The VRAM 11 c stores data (data suchas polygon data and texture data, etc.) required by the GPU 11 a toexecute graphics commands.

The DSP 11 c, which functions as an audio processor, generates audiodata to be played back, using sound data and tone quality data stored inthe internal main memory 11 d or the external main memory 12.

Image data and audio data generated by the game device 3 are read out bythe AV-IC 15. The AV-IC 15 outputs the read image data to the television2 via an AV connector 16, and outputs the read audio data to theloudspeaker 2 a provided in the television 2. Thus, an image isdisplayed on the television 2 while sound is output from the loudspeaker2 a.

The game device 3 can receive operation data from the controller 5.Specifically, the system LSI 11 receives operation data transmitted fromthe controller 5 via the antenna 23 and the controller communicationmodule 19, and stores (temporarily) the data in a buffer area of theinternal main memory 11 d or the external main memory 12.

Note that the game system 1 is merely illustrative, and a game process(information process) described below may be performed by any system.

General Description of Game Process

Next, a game process executable in the game system 1 of this embodimentwill be generally described. FIG. 2 is an example non-limiting diagramshowing video (image) which is displayed on the television 2 when a gameof this embodiment is executed. As shown in FIG. 2, a player character51, and a sound source 52 a, a sound source 52 b, and a sound source 52c (hereinafter also simply collectively referred to as a “sound source52”), are displayed on the television 2. In this embodiment, the playercharacter 51 is provided in a three-dimensional game space (virtualspace). An image of the game space is captured by a virtual cameraprovided behind the player character 51. The image containing the playercharacter 51 is displayed on the television 2. A gazing point of thevirtual camera is set to a head portion of the player character 51. Aplayer plays the game by moving the player character 51 in the gamespace or killing or beating an enemy character appearing in the gamespace using the controller 5. In the game of this embodiment, a varietyof game scenes are prepared. For example, there are a game scene thatthe player character 51 is surrounded by waterfalls and a river (FIG.2), a game scene that the player 51 is in a cave, etc.

The sound source 52 is a virtual object provided in the game space, andmore specifically, a waterfall object which appears to emit a sound. Asound of the sound source 52 is actually output from the loudspeaker 2 aso that it appears that the sound is generated at the location of thesound source 52 (a predetermined location in a region where thewaterfall object is displayed), and the game device 3 collects the soundusing a virtual microphone provided in the game space, before the soundis output from the loudspeaker 2 a.

FIG. 3 is an example non-limiting diagram showing each object in thegame space as viewed from above, indicating a location relationshipbetween each object in the game space. As shown in FIG. 3, the soundsources 52 a-52 c are provided around the player character 51, and avirtual camera 60 is provided at a predetermined distance from theplayer character 51. In the game space, a localization calculationmicrophone 61 and a volume calculation microphone 62 are also provided.The localization calculation microphone 61 is located at the location ofthe virtual camera 60. The volume calculation microphone 62 is locatedon an imaging axis of the virtual camera 60 at a predetermined location(e.g., a middle) between the gazing point of the virtual camera 60 (thelocation of the player character 51) and the virtual camera 60. When theplayer moves the player character 51 in the game space or changes theorientation of the player character 51 using the controller 5 (e.g., thecross button of the controller 5), the location and orientation of thevirtual camera 60 are changed. In the example of FIG. 3, the gazingpoint of the virtual camera 60 is fixed to the head portion of theplayer character 51, and is moved as the player character 51 moves.

The localization calculation microphone 61 is used to localize, orcalculate the location of, the sound source 52. The localizationcalculation microphone 61 is not displayed on the television 2. Here,the location of the sound source 52 is information about a locationrelationship between the localization calculation microphone 61 (thevirtual camera 60) and the sound source 52, i.e., a relative location ofthe sound source 52 with reference to the localization calculationmicrophone 61 (the term “location” in this sense is referred to as a“localized position”). The localized position of the sound source 52 maybe information indicating a direction of the sound source 52 withreference to the localization calculation microphone 61 or informationindicating the direction and distance of the sound source 52 withreference to the localization calculation microphone 61. In thisembodiment, the localized position of the sound source 52 is informationindicating the direction of the sound source 52 with reference to thelocalization calculation microphone 61 (as viewed from the localizationcalculation microphone 61), and is specifically represented as aleft-right position and a front-back position described below. Thevolume calculation microphone 62 is used to calculate a volume (e.g., anamplitude etc.) of a sound of a sound source. The volume calculationmicrophone 62 is not display on the television 2. The localizationcalculation and the volume calculation will be described below.

FIG. 4 is an example non-limiting diagram showing another example video(image) displayed on the television 2 when the game of this embodimentis executed. As shown in FIG. 4, in another scene of the game of thisembodiment, a character 55 moves in the game space surrounded by a wallobject. In the example of FIG. 4, the character 55, the location,orientation, and gazing point of the virtual camera 60, and otherobjects provided in the game space are automatically controlled by thegame device 3 irrespective of the player's operation. The game of thisembodiment is executable in a player operation mode (FIG. 2) in whichthe game proceeds while the player character 51 is controlled by theplayer's operation and in a demonstration mode (FIG. 4) in which thegame proceeds while the character 55 is moved and the gazing point ofthe virtual camera is changed without the player's operation. Note thatthe character 55 may or may not be the player character 51. In thedemonstration mode, the character 55 may not be displayed and thevirtual camera 60 may be automatically moved in the game space so thatan audience is caused to view video of other objects in the game spaceor listen to sounds.

For example, the game scene of FIG. 4 shows a door object (sound source53) which is being automatically opened. Here, as the door object (thesound source 53) is being opened, a sound occurs which is similar to asound generated when an actual door is being opened. In other words, thesound source 53 is a virtual object serving as a sound source whichappears to generate a sound. Also, when the door object (the soundsource 53) is automatically opened, the gazing point of the virtualcamera 60 is moved from the head portion of the character 55 tosomewhere in the vicinity of the sound source 53.

FIG. 5 is an example non-limiting diagram showing each object in thegame space as viewed from above when the image of FIG. 4 is displayed,indicating a location relationship between each object provided in thegame space. As shown in FIG. 5, the gazing point of the virtual camera60 is located in the vicinity of the sound source 53, and the volumecalculation microphone 62 is located in the vicinity of the gazingpoint. The volume of a sound of the sound source 53 is determined basedon a distance between the volume calculation microphone 62 and the soundsource 53. Because the volume calculation microphone 62 is located inthe vicinity of the sound source 53, the loudspeaker 2 a outputs arelatively large volume of sound (a sound effect which occurs when adoor is being opened). The volume calculation microphone 62 is fixed ata predetermined location in the vicinity of the gazing point of thevirtual camera 60. If, in the scene of FIG. 4, the gazing point of thevirtual camera 60 is located at the head portion of the character 55,the distance between the volume calculation microphone 62 and the soundsource 53 is relatively large because the volume calculation microphone62 is also located in the vicinity of the character 55. Therefore, ifthe gazing point of the virtual camera 60 is located at the head portionof the character 55, the loudspeaker 2 a outputs a relatively smallvolume of sound. Actually, however, as shown in FIGS. 4 and 5, thegazing point of the virtual camera 60 is set in the vicinity of thesound source 53, the loudspeaker 2 a outputs a relatively large volumeof sound when the door object (the sound source 53) is being opened.

The gazing point of the virtual camera 60 is changed based on theplayer's operation or is automatically changed by the game device 3. Forexample, in the player operation mode (FIG. 2), the gazing point of thevirtual camera 60 is fixed at the head portion of the player character51, and therefore, when the player moves the player character 51 usingthe controller 5, the gazing point of the virtual camera 60 is alsomoved. The volume calculation microphone 62 is set at a location betweenthe virtual camera 60 and the player character 51 which is determinedbased on the gazing point of the virtual camera 60. As the playercharacter 51 is moved by the player's operation, the volume calculationmicrophone 62 is also moved. Therefore, the volume of a sound of a soundsource located around the player character 51 is allowed to berelatively large.

In the demonstration mode (FIG. 4), the gazing point of the virtualcamera 60 is automatically changed by the game device 3, and the volumecalculation microphone 62 is fixed in the vicinity of the gazing pointof the virtual camera 60. In the demonstration mode, a game creator maywant the player (audience) to pay attention to a specific object in somegame scenes, and produce a program which causes the gazing point of thevirtual camera 60 to move to the specific object. For example, as shownin FIG. 4, in a game scene that the door object (the sound source 53) isautomatically opened so that the character 55 is guided along a pathahead of the sound source 53, the gazing point of the virtual camera 60is set in the vicinity of the sound source 53 in order to cause theaudience to pay attention to the door object. In such a game scene, thegazing point of the virtual camera 60 is set in the vicinity of the doorobject, and the volume of a sound of the sound source 53 output from theloudspeaker 2 a is set to be relatively large. As a result, the audienceis allowed to pay attention to the door object.

In the player operation mode and the demonstration mode, the gazingpoint of the virtual camera 60 may be allowed to be set at a specificobject by an operation performed by the player (or the audience). Whenthe player (or the audience) performs an operation to set the gazingpoint of the virtual camera 60 at a specific object, the player (or theaudience) may desire to pay attention to the object. Therefore, bysetting the volume of a sound of the specific object output from theloudspeaker 2 a to be relatively large, the player (or the audience) isallowed to pay attention to the object.

Next, the localization calculation and the volume calculation will bedescribed with reference to FIGS. 6-9. FIG. 6 is an example non-limitingdiagram showing the volume of a sound of the sound source 53 which isdetermined based on the distance between the volume calculationmicrophone 62 and the sound source 53. As shown in FIG. 6, the volume ofa sound of the sound source 53 varies depending on the distance betweenthe volume calculation microphone 62 and the sound source 53. The volumeof a sound of the sound source 53 is determined within the range of, forexample, 0 to 1.0. For example, when the sound source 53 and the volumecalculation microphone 62 are located at the same location, the volumeof a sound of the sound source 53 is set to the maximum value of 1.0.When the sound source 53 is located at a predetermined distance or morefrom the volume calculation microphone 62, the volume of a sound of thesound source 53 is set to zero, and in this case, the loudspeaker 2 adoes not output the sound. For example, the volume of a sound of thesound source 53 may be set to be proportional to the distance betweenthe volume calculation microphone 62 and the sound source 53. Forexample, as shown in FIG. 6, when the distance between the volumecalculation microphone 62 and the sound source 53 is L1, the volume of asound of the sound source 53 is set to 0.9. Specifically, when the soundsource 53 is located at any location on a circle having a radius of L1with the center of the circle located at the volume calculationmicrophone 62, the volume of a sound of the sound source 53 is set to0.9. Similarly, the volume of a sound of the sound source 52 (waterfallobject) varies depending on a distance between the sound source 52 andthe volume calculation microphone 62. The volume of the same sound ofthe same sound source is determined based on the distance between thevolume calculation microphone 62 and the sound source, and the volumesof sounds of different sound sources may be determined separately. Forexample, when the sound source 52 and the sound source 53 are located atequal distances from the volume calculation microphone 62, the volume ofa sound of the sound source 52 output from the loudspeaker 2 a may belarger than the volume of a sound of the sound source 53 output from theloudspeaker 2 a. For example, each sound source may be set to have abase volume, and the game device 3 may multiply the base volume by acoefficient varying depending on the distance between the sound sourceand the volume calculation microphone 62 (a coefficient varying withinthe range of 0 to 1.0, depending on the distance) to calculate a volumecorresponding to the distance. A single sound source may outputdifferent sounds which have different base volumes. In this case, thegame device 3 may multiply the base volumes of the different sounds by acoefficient corresponding to the distance between the sound source andthe volume calculation microphone 62 to calculate the respective volumescorresponding to the distance.

FIG. 7 is an example non-limiting diagram showing determination(left-right localization) of a localized position in a left-rightdirection (left-right position) of the sound source 53. The sound source53 is localized based on a location relationship between the soundsource 53 and the localization calculation microphone 61. Specifically,the localized position of the sound source 53 indicates a relativelocation and orientation of the sound source 53 as viewed from thelocalization calculation microphone 61 (with reference to thelocalization calculation microphone 61). More specifically, thelocalized position of the sound source 53 is represented by a left-rightposition and a front-back position.

The left-right position of the sound source 53 indicates how far thesound source 53 is located away from the localization calculationmicrophone 61 (the virtual camera 60) in the left-right direction, i.e.,indicates the left-right direction of the sound source 53 with referenceto the localization calculation microphone 61 (the virtual camera 60).Specifically, the left-right position of the sound source 53 isdetermined based on an angle D1 between an imaging direction vector ofthe virtual camera 60 and a vector from the localization calculationmicrophone 61 toward the sound source 53. It is assumed that an anglemeasured clockwise from the imaging direction (zero degrees) of thevirtual camera 60 is a positive angle. For example, when the soundsource 53 has an angle D1 within the range of 60 to 120 degrees, theleft-right position of the sound source 53 is determined to be 1.0. Forexample, when the sound source 53 has an angle D1 within the range of−60 to −120 degrees, the left-right position of the sound source 53 isdetermined to be −1.0. When the sound source 53 has an angle D1 of 0 to60 degrees, the left-right position of the sound source 53 is determinedwithin the range of 0 to 1.0. For example, the left-right position ofthe sound source 53 may be determined by a sine function which takes theangle D1 as a parameter or may be determined in proportion to the valueof the angle D1. When the sound source 53 has an angle D1 of 0 to −60degrees, the left-right position of the sound source 53 may bedetermined within the range of 0 to −1.0. For example, the left-rightposition of the sound source 53 may be determined by a sine functionwhich takes the angle D1 as a parameter or may be determined inproportion to the value of the angle D1. When the sound source 53 has anangle D1 of 120 to 180 degrees, the left-right position of the soundsource 53 may be determined within the range of 1.0 to 0, and when thesound source 53 has an angle D1 of −120 to −180 degrees, the left-rightposition of the sound source 53 may be determined within the range of−1.0 to 0. For example, in the case of FIG. 7, the sound source 53 islocated leftward away by a small amount from the localizationcalculation microphone 61 in the left-right direction, i.e., has a smallnegative angle D1, and therefore, the left-right position of the soundsource 53 is −0.1.

FIG. 8 is an example non-limiting diagram showing determination(front-back localization) of a localized position in a front-backdirection (front-back position) of the sound source 53. The front-backposition of the sound source 53 indicates how far the sound source 53 islocated away from the localization calculation microphone 61 (thevirtual camera 60) in the front-back direction, i.e., indicates thefront-back direction of the sound source 53 with reference to thelocalization calculation microphone 61 (the virtual camera 60).Specifically, the front-back position of the sound source 53 isdetermined based on an angle D2 between a rightward vector relative tothe imaging direction of the virtual camera 60 and a vector from thelocalization calculation microphone 61 toward the sound source 53. It isassumed that an angle measured clockwise from the direction (zerodegrees) of the rightward vector is a positive angle. For example, whenthe sound source 53 has an angle D2 within the range of 60 to 120degrees, the front-back position of the sound source 53 is determined tobe 1.0. For example, when the sound source 53 has an angle within therange of −60 to −120 degrees, the front-back position of the soundsource 53 is determined to be −1.0. When the sound source 53 has anangle D2 of 0 to 60 degrees, the front-back position of the sound source53 is determined within the range of 0 to 1.0. For example, thefront-back position of the sound source 53 may be determined by a sinefunction which takes the angle D2 as a parameter or may be determined inproportion to the value of the angle D2. When the sound source 53 has anangle D2 of 0 to −60 degrees, the front-back position of the soundsource 53 may be determined within the range of 0 to −1.0. For example,the front-back position of the sound source 53 may be determined by asine function which takes the angle D2 as a parameter or may bedetermined in proportion to the value of the angle D2. When the soundsource 53 has an angle D2 of 120 to 180 degrees, the front-back positionof the sound source 53 may be determined within the range of 1.0 to 0,and when the sound source 53 has an angle D2 of −120 to −180 degrees,the front-back position of the sound source 53 may be determined withinthe range of −1.0 to 0. For example, in the case of FIG. 8, the soundsource 53 is located in front of the localization calculation microphone61, and therefore, the front-back position of the sound source 53 is−1.0.

It is assumed that the localized position of the sound source 53 is notchanged in an up-down direction (vertical direction) in the game space.Specifically, it is assumed that when the sound source 53 and thelocalization calculation microphone 61 are located on a predeterminedplane (ground) in the game space, then even if the sound source 53 orthe localization calculation microphone 61 is moved in an up-downdirection (a direction perpendicular to the predetermined plane) in thegame space, the localized position of the sound source 53 is notchanged.

FIG. 9 is an example non-limiting diagram showing the left-rightposition, front-back position, and volume of the sound source 53 whenthe localization calculation microphone 61, the volume calculationmicrophone 62, and the sound source 53 have a predetermined locationrelationship. As shown in FIG. 9, when the sound source 53 is locatedsubstantially directly in front of the virtual camera 60 and is locatedleftward away by a small amount from the imaging direction of thevirtual camera 60, i.e., has a slightly small negative angle D1, thefront-back position and left-right position of the sound source 53 are−1.0 and −0.1, respectively. When the sound source 53 is relativelyclose to the volume calculation microphone 62, the volume is 0.9.

When a sound of the sound source 53 is output from the loudspeaker 2 a,the player can localize, or identify the location of, the sound source53. For example, if the left-right position is 0 and the front-backposition is −1, the player recognizes that the sound occurs in front ofthe player. If the left-right position is 0 and the front-back positionis 1, the player recognizes that the sound occurs behind the player. Ifthe left-right position is 1 and the front-back position is 0, theplayer recognizes that the sound occurs to the right of the player. Ifthe left-right position is −1 and the front-back position is 0, theplayer recognizes that the sound occurs to the left of the player. Asshown in FIG. 9, the localization calculation microphone 61 is set atthe location of the virtual camera 60, and therefore, the playerrecognizes that a sound comes from the sound source 53 (in a directionfrom the sound source 53 toward the virtual camera 60), i.e., the soundis generated by the sound source 53.

On the other hand, the volume calculation microphone 62 is set based onthe gazing point of the virtual camera 60. In the example of FIG. 9, thevolume calculation microphone 62 is provided in the vicinity of thesound source 53. Therefore, a sound of the sound source 53 is output bythe loudspeaker 2 a at a relatively large volume. For example, if thevolume calculation microphone 62 also serves as the localizationcalculation microphone 61, then when the volume calculation microphone62 is located at the location of the virtual camera 60, the distancebetween the sound source 53 and the volume calculation microphone 62(the localization calculation microphone 61) is large. Therefore, asound of the sound source 53 has a relatively low volume. On the otherhand, if the volume calculation microphone 62 also serves as thelocalization calculation microphone 61, then when the volume calculationmicrophone 62 (the localization calculation microphone 61) is set in thevicinity of the sound source 53 in order to increase the volume of asound of the sound source 53, the localization of the sound source 53 isaffected or altered. For example, if the localization calculationmicrophone 61 is located at the same location (FIG. 9) where the volumecalculation microphone 62 is located, the sound source 53 is locatedsubstantially to the left of the localization calculation microphone 61,and therefore, the front-back position and left-right position of thesound source 53 as viewed from the localization calculation microphone61 are 0 and −1.0, respectively. Therefore, when the player hears asound of the sound source 53 while viewing an image captured by thevirtual camera 60, the player recognizes that a sound comes from a placeother than the sound source 53 displayed on the television 2 (a place tothe left of the sound source 53), i.e., a sound of the sound source 53comes from a different place or the sound is not generated from thesound source 53. Therefore, if the localization calculation microphone61 is provided close to the sound source 53, a sound of the sound source53 may appear unnatural to the player. However, in the game of thisembodiment, the volume calculation microphone 62 and the localizationcalculation microphone 61 are provided separately, and the volumecalculation microphone 62 is provided close to a sound source, wherebythe volume of a sound of the sound source can be changed withoutaffecting or altering the localization of the sound source.

If the volume calculation microphone 62 is provided at the same locationwhere the localization calculation microphone 61 (the virtual camera 60)is provided, then when another object which is not covered by thevirtual camera 60 is provided in the vicinity of the virtual camera 60,the volume of a sound of this object which is not displayed on thetelevision 2 may be large. If the volume of a sound of an object whichis not displayed on the television 2 is large, the player may feelunnatural or be confused. However, in this embodiment, the volumecalculation microphone 62 and the localization calculation microphone 61are provided separately. In the demonstration mode, the volumecalculation microphone 62 is provided in the vicinity of the gazingpoint of the virtual camera 60. In the player operation mode, the volumecalculation microphone 62 is provided between the player character 51and the virtual camera 60. Therefore, the volume of a sound of an objectwhich is not covered by the virtual camera 60 can be reduced, and thevolume of a sound of an object which is located in the vicinity of thegazing point of the virtual camera 60 or around the player character 51and the virtual camera 60 can be increased.

Next, a process for a sound emitted by an object moving in the gamespace will be described. FIG. 10 is an example non-limiting diagramshowing a movement of an arrow object (sound source 54) toward thevirtual camera 60 in the game space as viewed from above. As shown inFIG. 10, in the game of this embodiment, the Doppler effect microphone63 is set in the game space in addition to the localization calculationmicrophone 61 and the volume calculation microphone 62. The Dopplereffect microphone 63 is a virtual microphone which is not displayed onthe television 2. Although, in FIG. 10, the Doppler effect microphone 63is displayed at a location away from the localization calculationmicrophone 61, in this embodiment the Doppler effect microphone 63 isset at the location of the localization calculation microphone 61.Therefore, the Doppler effect microphone 63 may not be internallydefined, and a process described below may be performed, assuming thatthe localization calculation microphone 61 also serves as the Dopplereffect microphone 63.

The arrow object is an object which moves at a velocity v in the gamespace while emitting a sound (sound effect) which is generated by thefriction between the arrow and air when the arrow is moving in the air.In the game of this embodiment, the frequency of a sound emitted fromthe arrow object (the sound source 54) is corrected, taking intoconsideration the Doppler effect of the movement of the arrow object.Also, when the Doppler effect microphone 63 (the virtual camera 60)moves in the game space, the sound of the sound source 54 is correctedbased on the Doppler effect. Specifically, the sound of the sound source54 is corrected based on a relative motion of the sound source 54 andthe Doppler effect microphone 63. More specifically, the frequency ofthe sound of the sound source 54 varies depending on the velocity of thesound source 54 and the velocity of the Doppler effect microphone 63.Therefore, for example, when the sound source 54 approaches and passesby the Doppler effect microphone 63, the sound of the sound source 54changes.

Although, in this embodiment, the Doppler effect microphone 63 islocated at the location of the localization calculation microphone 61(the virtual camera 60), the Doppler effect microphone 63 may be locatedaway from the localization calculation microphone 61. For example, asshown in FIG. 10, the Doppler effect microphone 63 may be located at apredetermined location in the imaging direction of the virtual camera60. In this case, when the sound source 54 moving toward the virtualcamera 60 passes by the Doppler effect microphone 63, the frequency ofthe sound of the sound source 54 changes. At this time, the sound source54 is located in front of the virtual camera 60. In other words, thetime that the passing of the sound source 54 is detected auditorilyprecedes the time that the passing of the sound source 54 is detectedvisually. The Doppler effect microphone 63 may be provided in thevicinity of the player character 51. In this case, the Doppler effectwhich is recognized at the location of the player character 51 can bereproduced.

Process on Sound From Behind

Next, a sound process which is performed when a sound source is locatedbehind the virtual camera 60 will be described with reference to FIGS.11-13. FIG. 11 is an example non-limiting diagram showing each object inthe game space as viewed from above, where the sound source 52 islocated behind the virtual camera 60. As shown in FIG. 11, a back filtermicrophone 64 is provided at the location of the virtual camera 60 (thelocalization calculation microphone 61). In this embodiment, when thesound source 52 is located behind the virtual camera 60 (on a sideopposite to the imaging direction of the virtual camera 60), a filteringprocess is performed on a sound of the sound source 52. In the filteringprocess, a frequency filter (a low-pass filter, a band-pass filter, ahigh-pass filter, etc.) is applied to the sound so that the volume of aspecific frequency component is reduced or a specific frequencycomponent is removed. For example, in the filtering process employing alow-pass filter, components higher than or equal to a predeterminedfrequency are removed. In this embodiment, a low-pass filter or aband-pass filter is used to remove higher frequency components, wherebya sound coming from the virtual camera 60 is muffled.

FIG. 12 is an example non-limiting diagram showing a filter value basedon a location relationship between the back filter microphone 64 and thesound source 52. As shown in FIG. 12, when the sound source 52 islocated in front of the virtual camera 60 (the back filter microphone64), the filter value is set to zero. In this case, a filter is notapplied to a sound of the sound source 52, and therefore, the sound isdirectly output from the loudspeaker 2 a. The filter value indicates thedegree of filtering (the degree of correction) of a sound. The filtervalue will be described below.

On the other hand, when the sound source 52 is located behind thevirtual camera 60, the filter value is set within the range of 0 to 1.Specifically, initially, an angle D1 between the imaging directionvector of the virtual camera 60 and a vector from the back filtermicrophone 64 toward the sound source 54 is calculated. Also, a distanceL2 between the back filter microphone 64 and the sound source 52 iscalculated. Thereafter, the filter value is calculated based on theangle D1 and the distance L2. Specifically, when the absolute value ofthe angle D1 is 0 to 90 degrees, the filter value is set to 0. When theabsolute value of the angle D1 is 90 to 180 degrees, then if thedistance L2 is larger than or equal to a threshold value Lm, the filtervalue is set to a maximum value (≦1) which depends on the absolute valueof the angle D1. When the absolute value of the angle D1 is 90 to 180degrees, then if the distance L2 is smaller than the threshold value Lm,the filter value is calculated by correcting (reducing), based on thedistance L2, the maximum value depending on the angle D1. For example,the maximum value depending on the angle D1 may be determined inproportion to the angle D1 or using a sine function which takes theangle D1 as a parameter. For example, when the absolute value of theangle D1 is 180 degrees, the maximum value of the filter value is setto 1. When the distance L2 is smaller than the threshold value Lm, thefilter value may be calculated by dividing the distance L2 by thethreshold value Lm, for example. For example, when the absolute value ofthe angle D1 is 135 degrees, the maximum value may be set to 0.5, andwhen the distance L2 is ½ of the threshold value Lm, the filter valuemay be set to ½ of the maximum value, i.e., 0.25.

Note that when the distance L2 between the back filter microphone 64 andthe sound source 52 is smaller than a threshold value L0 (<Lm), theneven if the absolute value of the angle D1 is greater than 90 degrees,i.e., the sound source 52 is located behind the virtual camera 60, thefilter value is set to 0. Therefore, when the sound source 52 is locatedwithin the range of the threshold value L0 from the back filtermicrophone 64, a sound of the sound source 52 is directly output fromthe loudspeaker 2 a without applying a filter to the sound.

As used herein, the term “filter value” refers to the degree ofcorrection of a sound of a sound source. FIG. 13 is an examplenon-limiting diagram showing frequency filtering, where different filtervalues are used. In FIG. 13, the horizontal axis indicates frequencies,and the vertical axis indicates volume ratios. As shown in FIG. 13, whenthe filter value is 0, the volume ratio is 1 over all frequencies.Therefore, the volume of each frequency component of a sound ismaintained, and a sound of a sound source is directly output from theloudspeaker 2 a. On the other hand, when the filter value is, forexample, 0.5, the volumes of frequency components higher than a specificfrequency F0 are corrected based on a curve indicated by the filtervalue of 0.5. For example, as shown in FIG. 13, when the filter value is0.7, the volume of a component having a frequency F1 is set to be 0.7times as large as the volume before correction. For example, when thefilter value is 1, the volumes of components having the frequency F0 orhigher are set to 0, and therefore, the components having the frequencyF0 or higher are removed. Thus, a sound is corrected using a filtervalue, and the corrected sound is output from the loudspeaker 2 a.Specifically, when the low-pass filter of FIG. 13 is applied to a sound,higher frequency components of the sound are removed or attenuated, andtherefore, the corrected sound becomes muffled. Note that the filtercurves of FIG. 13 (the curve portions at the frequency F0 or higher) mayhave any shape. For example, the portion at the frequency F0 or highermay be in the shape of a straight line or a curve which converges to apredetermined volume (ratio). Although, in FIG. 13, the vertical axisindicates volume ratios, the vertical axis may indicate values by whichthe volume is reduced.

As described above, in this embodiment, when a sound source is locatedbehind the virtual camera 60 (the absolute value of the angle D1 iswithin the range of 90 to 180 degrees), a frequency filter is applied toa sound of the sound source. Specifically, as the sound source islocated closer to a location directly behind the virtual camera 60(i.e., the absolute value of the angle D1 is closer to 180 degrees), thefilter value increases (the degree of correction increases). Inaddition, as the sound source is located further away from the virtualcamera 60, the filter value increases (the degree of correctionincreases). As a result, as the sound source is located closer to alocation directly behind the virtual camera 60 (i.e., the absolute valueof the angle D1 is closer to 180 degrees), the sound of the sound sourcebecomes more muffled, and as the sound source is located further awayfrom the virtual camera 60, the sound of the sound source becomes moremuffled. Therefore, the player can recognize a direction in which thesound source is located (where the sound source is located on a sideopposite to the imaging direction of the virtual camera 60). When asound source is located behind the virtual camera 60, the sound sourceis not displayed on the television 2. Therefore, if a sound of an objectwhich is not displayed is muffled, the player is allowed to payattention to another object which is displayed on the television 2.Also, even when there are a plurality of identical sound sources in thegame space, the player can listen to a sound of an object displayed onthe television 2 without being confused.

Details of Game Process

Next, details of the game process executed in this game system will bedescribed. Firstly, various data items used in the game process will bedescribed. FIG. 14 is an example non-limiting diagram showing variousdata items used in the game process. FIG. 14 shows main data itemsstored in a main memory (the external main memory 12 or the internalmain memory 11 d) of the game device 3. As shown in FIG. 14, the mainmemory of the game device 3 stores a game program 100 and processingdata 110. Note that the main memory stores, in addition to the dataitems of FIG. 14, other data items required for the game, such as imagedata of each object appearing in the game, audio data of BGM of thegame, etc.

A portion of or the entire game program 100 is read from the opticaldisc 4 into the main memory with appropriate timing after the gamedevice 3 is turned on. The game program 100 may be obtained from a flashmemory 17 or a device external to the game device 3 (via, for example,the Internet) instead of the optical disc 4. A portion of the gameprogram 100 may be previously stored in the game device 3.

The processing data 110 is used in a main process described below (FIG.15). The processing data 110 contains character data 111, sound sourcedata 112, virtual camera data 113, and microphone data 114.

The character data 111 contains data indicating the location andorientation in the game space of the player character 51. The characterdata 111 also contains data indicating the location and orientation inthe game space of the character 55.

The sound source data 112 relates to each object serving as a soundsource. The sound source data 112 contains data relating to the soundsource 52 (waterfall object), the sound source 53 (door object), thesound source 54 (arrow object), etc. Specifically, data relating tosound sources contains data indicating the location and orientation ofeach sound source, data indicating the localized position of each soundsource, audio data (data indicating the waveform of a sound) of eachsound source, data indicating the volume of a sound of each soundsource, etc.

The virtual camera data 113 contains data indicating the location,orientation, and gazing point of the virtual camera 60.

The microphone data 114 relates to each microphone. Specifically, themicrophone data 114 contains data relating to the localizationcalculation microphone 61, the volume calculation microphone 62, theDoppler effect microphone 63, and the back filter microphone 64. Morespecifically, the microphone data 114 contains data indicating thelocation and orientation of the localization calculation microphone 61,data indicating the location and orientation (or only the location) ofthe volume calculation microphone 62, data indicating the location andorientation (or only the location) of the Doppler effect microphone 63,and data indicating the location and orientation of the back filtermicrophone 64. Note that, in this embodiment, the localizationcalculation microphone 61 and the virtual camera 60 have the samelocation and orientation. The Doppler effect microphone 63 and thelocalization calculation microphone 61 have the same location andorientation. The back filter microphone 64 and the localizationcalculation microphone 61 have the same location and orientation. Inother words, the microphones 61, 63, and 64 have the same location andorientation as those of the virtual camera 60. Therefore, the datarelating to the localization calculation microphone 61, the Dopplereffect microphone 63, and the back filter microphone 64 may not bestored in the main memory. In other words, the virtual camera data 113may be used as the data relating to the microphones 61, 63, and 64 inthe main process described below.

Description of Flowchart

Next, the game process executed in the game device 3 will be describedin detail with reference to FIGS. 15-17. FIG. 15 is an examplenon-limiting main flowchart showing a flow of the game process executedin the game device 3. When the game device 3 is turned on, the CPU 10 ofthe game device 3 executes a boot program stored in a boot ROM (notshown) to initialize units such as the main memory. The game programstored in the optical disc 4 is read into the main memory, and the CPU10 begins to execute the game program. The CPU 10 also reads audio dataof a sound source stored on the optical disc 4 into the main memory. Theprocess of the flowchart of FIG. 15 is executed after the above processhas been completed.

The steps of the flowcharts of FIGS. 15-17 are merely illustrative, andthe order in which the steps are performed may be changed as long assimilar advantages are obtained. The values of variables and constants,etc., are also merely illustrative, and other values may be optionallyused. In this embodiment, it is assumed that the steps of the flowchartsare executed by the CPU 10. Alternatively, a portion of the steps may beexecuted by a processor or a dedicated circuit other than the CPU 10.

In step S1, the CPU 10 executes an initial process. In the initialprocess, the CPU 10 sets the game mode to the player operation mode orthe demonstration mode based on the player's selection. The CPU 10 alsoconstructs a three-dimensional game space, arranges at initial locationsthe player character 51, the character 55, the sound sources 52-54, thelocalization calculation microphones 61-64, the virtual camera 60, andother objects appearing in the game space. The CPU 10 also sets variousparameters used in the game process to initial values. After step S1,the CPU 10 executes step S2. Thereafter, a loop of steps S2-S9 isrepeatedly executed at a rate of once per predetermined period of time(one frame time, e.g., 1/60 sec).

In step S2, the CPU 10 obtains operation data which has been transmittedfrom the controller 5 and stored in the main memory. The controller 5repeatedly transmits operation data (data relating to an operationperformed on each button, etc.) to the game device 3 at predeterminedintervals. In the game device 3, the controller communication module 19sequentially receives operation data, which is then sequentially storedinto the main memory. In step S2, the CPU 10 reads latest operation datafrom the main memory. After step S2, step S3 is executed.

In step S3, the CPU 10 executes the game process. In the game process,the CPU 10 moves the player character 51 in the game space, changes theorientation of the player character 51, and changes the location and/ororientation of the virtual camera 60 based on the operation dataobtained in step S2. The CPU 10 also changes the location and/ororientation of each microphone (61-63). The CPU 10 also moves the soundsource 54 and other objects (e.g., an enemy character, etc.). Note thatwhen the game device 3 is operating in the demonstration mode, the CPU10 moves the character 55 and changes the location and orientation ofthe virtual camera 60 in accordance with a predetermined algorithm.Next, the CPU 10 executes step S4.

In step S4, the CPU 10 executes a localization/volume calculationprocess. In the localization/volume calculation process, the CPU 10calculates the localized position and volume of each sound source. Thelocalization/volume calculation process will be described in detailhereinafter with reference to FIG. 16.

FIG. 16 is an example non-limiting flowchart showing a detailed flow ofthe localization/volume calculation process (step S4) of FIG. 15.

In step S11, the CPU 10 selects one sound source (e.g., the sound source52 a) to be processed from a plurality of sound sources provided in thegame space. After step S11, the CPU 10 executes step S12. Note that ifthere is no sound source object in the game space, the CPU 10 ends thelocalization/volume calculation process.

In step S12, the CPU 10 calculates the volume of a sound based on thedistance between the sound source selected in step S11 and the volumecalculation microphone 62. Specifically, the CPU 10 calculates thedistance between the sound source and the volume calculation microphone62 based on the location of the sound source and the location of thevolume calculation microphone 62 which are obtained by referencing themain memory. Thereafter, the CPU 10 calculates the volume based on thedistance. More specifically, as described above, the CPU 10 calculatesthe volume so that the volume decreases with an increase in the distance(the volume decreases in proportion to the distance). The calculatedvolume is stored in the main memory. Next, the CPU 10 executes step S13.

In step S13, the CPU 10 calculates the localized position of the soundsource selected in step S11 based on the angle between the sound sourceand the localization calculation microphone 61. Specifically, the CPU 10calculates the localized position (the left-right position and thefront-back position) of the sound source based on the location andorientation of the localization calculation microphone 61 and thelocation of the sound source which are obtained by referencing the mainmemory. More specifically, the CPU 10 calculates the angle D1 (FIG. 7)and the angle D2 to calculate the left-right position and front-backposition of the sound source. The calculated localized position isstored in the main memory. Next, the CPU 10 executes step S14.

In step S14, the CPU 10 calculates the Doppler effect based on therelative velocity between the sound source selected in step S11 and theDoppler effect microphone 63. Specifically, the CPU 10 correctsfrequency components of a sound of the selected sound source based onthe relative velocity. The result of calculation of the Doppler effectis stored in the main memory. Next, the CPU 10 executes step S15.

In step S15, the CPU 10 determines whether or not the process has beenexecuted for all sound sources. By repeatedly executing steps S11-S15,the process is executed for all sound sources provided in the gamespace. If the determination result is negative, the CPU 10 executes stepS11 again. On the other hand, if the determination result is positive,the CPU 10 ends the localization/volume calculation process.

Referring back to FIG. 15, next, in step S5, the CPU 10 executes thefiltering process. In the filtering process of step S5, the CPU 10applies a frequency filter to a sound of a sound source which isprovided behind the virtual camera 60 (the back filter microphone 64).The filtering process will be described in detail hereinafter withreference to FIG. 17.

FIG. 17 is an example non-limiting flowchart showing a detailed flow ofthe filtering process (step S5) of FIG. 15.

In step S21, the CPU 10 selects one sound source (e.g., the sound source52 a) to be processed from a plurality of sound sources provided in thegame space. After step S21, the CPU 10 executes step S22. Note that ifthere is no sound source object in the game space, the CPU 10 ends thefiltering process.

In step S22, the CPU 10 determines whether or not the sound sourceselected in step S21 is one to which a filter is to be applied. Whetheror not a sound source is one to which a filter is to be applied ispreviously determined, and for example, is determined based on the typeof the sound source. For example, if the sound source selected in stepS21 is the sound source 52 (waterfall object), the CPU 10 determinesthat the sound source is one to which a filter is to be applied. Notethat if a single sound source outputs a plurality of kinds of sound, foreach kind of sound it may be determined whether or not the sound is oneto which a filter is to be applied. In this case, it is previouslydetermined whether or not a sound is one to which a filter is to beapplied, according to the kind of the sound. If the determination resultis positive, the CPU 10 next executes step S23. On the other hand, ifthe determination result is negative, the CPU 10 next executes step S31.

In step S23, the CPU 10 calculates an angle between the sound source andthe microphone. Specifically, the CPU 10 calculates the angle D1 (seeFIG. 12) between the sound source and the back filter microphone 64 (thevirtual camera 60) based on the location and orientation of the backfilter microphone 64 (the virtual camera 60) and the location of thesound source which are obtained by referencing the main memory. Next,the CPU 10 executes step S24.

In step S24, the CPU 10 determines whether or not the sound source islocated behind the back filter microphone 64. Specifically, the CPU 10determines whether or not the absolute value of the angle D1 between thesound source and back filter microphone 64 calculated in step S23 isgreater than 90 degrees. If the determination result is positive, theCPU 10 next executes step S25. On the other hand, if the determinationresult is negative, the CPU 10 next executes step S29.

In step S25, the CPU 10 calculates a filter value based on the angle D1between the sound source and the back filter microphone 64. Here, asshown in FIG. 12, the CPU 10 calculates a maximum value (within therange of 0 to 1.0) of the filter value based on the angle D1 between thesound source and the back filter microphone 64. For example, the CPU 10calculates the maximum value of the filter value in proportion to theangle D1. Next, the CPU 10 executes step S26.

In step S26, the CPU 10 calculates a distance between the sound sourceand the back filter microphone 64. Specifically, the CPU 10 calculatesthe distance L2 (see FIG. 12) between the sound source and the backfilter microphone 64 by referencing the main memory. Next, the CPU 10executes step S27.

In step S27, the CPU 10 determines whether or not the distance L2between the sound source and the back filter microphone 64 calculated instep S26 is larger than or equal to the threshold value L0 (see FIG.12). If the determination result is positive, the CPU 10 next executesS28. On the other hand, if the determination result is negative, the CPU10 next executes S29.

In step S28, the CPU 10 corrects the filter value based on the distanceL2 between the sound source and the back filter microphone 64 calculatedin step S26. Here, the CPU 10 corrects the maximum value of the filtervalue calculated in step S25 based on the distance L2. If the distanceL2 between the sound source and the back filter microphone 64 is largerthan or equal to the threshold value Lm (see FIG. 12), the CPU 10 setsthe filter value to the maximum value calculated in step S25. If thedistance L2 between the sound source and the back filter microphone 64is smaller than the threshold value Lm, for example the CPU 10multiplies the maximum value calculated in step S25 by a value obtainedby dividing the distance L2 by the threshold value Lm, to correct themaximum value of the filter value calculated in step S25. The correctedfilter value is stored in the main memory. Next, the CPU 10 executesS30.

On the other hand, in step S29, the CPU 10 sets the filter value tozero. Here, because the sound source is not located behind the backfilter microphone 64 or the distance L2 between the sound source and theback filter microphone 64 is smaller than the threshold value L0, theCPU 10 sets the filter value to zero. As a result, when soundreproduction is performed, a sound to which no filter has been appliedis output from the loudspeaker 2 a. After step S29, the CPU 10 nextexecutes step S30.

In step S30, the CPU 10 applies a frequency filter to a sound. Here, theCPU 10 applies, to a sound of the sound source, a filter (see FIG. 13)corresponding to the filter value calculated in step S28. As a result,components higher than or equal to a predetermined frequency may beremoved (the volumes thereof are set to zero), or the volumes ofcomponents higher than or equal to a predetermined frequency may beattenuated. After step S30, the CPU 10 next executes step S31.

In step S31, the CPU 10 determines whether or not the process has beenexecuted for all sound sources. By repeatedly executing steps S21-S31,the process is executed for all sound sources provided in the gamespace. If the determination result is negative, the CPU 10 executes stepS21 again. On the other hand, if the determination result is positive,the CPU 10 ends the filtering process of FIG. 17.

Referring back to FIG. 15, the CPU 10 next executes an image datageneration process in step S6. In step S6, an image to be displayed onthe television 2 is generated. Specifically, the CPU 10 shoots the gamespace using the virtual camera 60 to generate image data. Next, the CPU10 executes step S7.

In step S7, the CPU 10 executes an image output process. Here, the imagedata generated in step S6 is output to the television 2. As a result, agame image is displayed on a screen of the television 2. Next, the CPU10 executes step S8.

In step S8, the CPU 10 executes an audio output process. By executingstep S8, a sound as a result of steps S4 and S5 is output from theloudspeaker 2 a. Specifically, audio data is generated based on thelocalized position and volume of the sound source and the Doppler effectcalculated in step S4, and moreover, is corrected based on the result ofthe filtering process of step S5. Thereafter, the CPU 10 outputs theaudio data via the system LSI 11 to the AV-IC 15. As a result, a soundis output from the loudspeaker 2 a. Next, the CPU 10 executes step S9.

In step S9, the CPU 10 determines whether or not the game is to beended. The determination in step S9 is performed based on, for example,whether or not the game is over (or cleared), or whether or not the userissues an instruction to end the game, etc. If the determination resultof step S9 is negative, step S2 is executed again. On the other hand, ifthe determination result of step S9 is positive, the CPU 10 ends themain process of FIG. 15.

As described above, in the game of this embodiment, a sound of a soundsource provided in the game space is corrected before being output fromthe loudspeaker 2 a. Specifically, the localized position (direction) ofa sound source is calculated with reference to the location of thelocalization calculation microphone 61 (the virtual camera 60). Thevolume of the sound is calculated based on the distance between thesound source and the volume calculation microphone 62 which is providedseparately from the localization calculation microphone 61. Thereafter,the sound corresponding to the calculated localized position of thesound source and the calculated volume is output from the loudspeaker 2a. In this embodiment, the localization calculation microphone 61 islocated at the location of the virtual camera 60, and the volumecalculation microphone 62 is located in the vicinity of the gazing pointof the virtual camera 60 (a predetermined location in the imagingdirection of the virtual camera 60). Therefore, the volume of the soundof the sound source can be increased while the localized position of thesound source displayed in the vicinity of the center of the television 2with reference to the virtual camera 60 is maintained. As a result, theplayer is allowed to pay attention to a predetermined object in the gamespace both visually and auditorily, and even when a large number ofobjects emitting a sound are provided in the game space, the player isallowed to pay attention to a specific object without being confused.

In the player operation mode, the volume calculation microphone 62 isprovided between the player character 51 and the virtual camera 60.Therefore, the volume of a sound of a sound source provided around theplayer character 51 can be further increased. For example, if the volumecalculation microphone 62 is provided at the location of the virtualcamera 60 (the localization calculation microphone 61 and the volumecalculation microphone 62 are provided at the same location), the volumeof a sound of an object which is not covered by the virtual camera 60 isincreased, so that the volume of a sound around the player character 51is decreased. Therefore, the player may feel unnatural, or if there area large number of sound sources, the player may be confused. However, inthe above embodiment, the volume calculation microphone 62 is providedbetween the player character 51 and the virtual camera 60, a largevolume of sound can be reproduced from the vicinity of the playercharacter 51, and therefore, the player can play the game without anunnatural sensation.

In the demonstration mode, the volume calculation microphone 62 isprovided in the vicinity of the gazing point of the virtual camera 60.Therefore, the volume of a sound of an object or region gazed by thevirtual camera 60 can be increased while the volumes of sounds of otherregions can be decreased, whereby the audience is allowed to payattention to the object.

Also, in this embodiment, a filtering process is performed on a sound ofa sound source located behind the virtual camera 60. Specifically, asthe sound source is located closer to a location directly behind thevirtual camera 60, the sound of the sound source is further corrected.Also, as the sound source is located further away from the virtualcamera 60, the sound of the sound source is further corrected.Specifically, in this embodiment, as the angle between the sound sourceand the virtual camera 60 increases (the angle approaches 180 degrees)or the distance between the virtual camera 60 and the sound sourceincreases, the sound of the sound source is further corrected (the soundof the sound source is further attenuated). As a result, a sound of anobject which is located behind the virtual camera 60 and therefore isnot displayed on the television 2 can be muffled and therebydistinguished from a sound occurring in front of the microphone.

For example, in order to differentiate sounds coming from a frontdirection and a back direction in the virtual three-dimensional spacefrom each other, the virtual surround sound technique in which a phasedifference or a time difference, etc., between two loudspeakers (stereoloudspeakers) is used, or the 5.1 channel surround sound technique inwhich loudspeakers are actually provided in front of and behind theaudience, etc., may be employed. However, in the virtual surround soundtechnique and the 5.1 channel surround sound technique, two or moreloudspeakers are required, and the distance between each loudspeaker andthe location relationship between the loudspeakers and the audience needto satisfy predetermined conditions. Moreover, the 5.1 channel surroundsound technique requires dedicated hardware, and the virtual surroundsound technique requires complicated calculation. However, in thisembodiment, in the filtering process, a sound can be corrected with arelatively low load and without the need of complicated calculation, andin addition, a monaural loudspeaker can be used to differentiate soundscoming from front and back directions.

Variations

The above embodiment is merely illustrative. In other embodiments, thefollowing configurations may be provided, for example.

For example, in the above embodiment, the localization calculationmicrophone 61 and the volume calculation microphone 62 are providedseparately, and the volume calculation microphone 62 is located at apredetermined location on the imaging axis of the virtual camera 60. Inanother embodiment, the volume calculation microphone 62 may be locatedat a predetermined location on a surface perpendicular to the imagingaxis of the virtual camera 60 instead of being located on the imagingaxis of the virtual camera 60. In other words, the volume calculationmicrophone 62 may be located at a predetermined location (an imagingrange which is not limited to the imaging axis) within the imaging rangeof the virtual camera 60.

In the above embodiment, the volume calculation microphone 62 is locatedat a predetermined location between the localization calculationmicrophone 61 (the virtual camera 60) and the gazing point of thevirtual camera 60 (the location of the player character 51). In anotherembodiment, the volume calculation microphone 62 may be located at thesame location where the gazing point of the virtual camera 60 islocated, or may be located further than the gazing point in the imagingdirection of the virtual camera 60.

In the above embodiment, the localization calculation microphone 61 islocated at the same location where the virtual camera 60 is located. Inanother embodiment, the localization calculation microphone 61 does notnecessarily need to be located at the location of the virtual camera 60.For example, the localization calculation microphone 61 may be locatedbased on the location of a player object (the localization calculationmicrophone 61 may be located at the same location where the playerobject is located, or at a location where the localization calculationmicrophone 61 and the player object have a predetermined relationship).

In the above embodiment, the volume calculation microphone 62 is locatedbased on the gazing point of the virtual camera 60. Specifically, in theplayer operation mode, the gazing point is set at the player character51, and the volume calculation microphone 62 is set between the playercharacter 51 and the virtual camera 60. In the demonstration mode, thevolume calculation microphone 62 is located in the vicinity of thegazing point of the virtual camera 60. In another embodiment, the volumecalculation microphone 62 may be located away from the gazing point ofthe virtual camera 60, and for example, may be moved by the player'soperation. For example, a microphone object indicating the volumecalculation microphone 62 may be displayed on the television 2, and maybe moved in the game space by the player's operation. When the playerdesires to pay attention to a sound of a specific sound source, theplayer may be allowed to increase the volume of the sound of thespecific sound source by moving the microphone object.

In the above embodiment, the Doppler effect microphone 63 is located atthe same location where the localization calculation microphone 61 islocated. In another embodiment, the Doppler effect microphone 63 and thelocalization calculation microphone 61 may not be located at the samelocation. For example, the Doppler effect microphone 63 may be providedin the vicinity of the player character 51.

In the above embodiment, the localized position of a sound source isrepresented by a left-right position and a front-back position which areeach represented by a predetermined value (a value within the range of−1.0 to 1.0) corresponding to the angle between the sound source and thelocalization calculation microphone 61. In another embodiment, thelocalized position of a sound source may be calculated in any manner aslong as a location relationship between the sound source and thelocalization calculation microphone 61 is represented. For example, thelocalized position of a sound source may be represented by coordinatevalues of a coordinate system fixed to the localization calculationmicrophone 61. The localized position of a sound source may indicate adirection of the sound source, or the direction and distance of thesound source, with reference to the localization calculation microphone61.

In the above embodiment, the localized position of a sound source iscalculated only in the left-right direction and the front-backdirection. Specifically, in the above embodiment, a localized positionon a two-dimensional plane (ground) is calculated, and it is assumedthat even when a sound source or the localization calculation microphone61 is moved in an up-down direction in the virtual space, the localizedposition of the sound source is not changed. In another embodiment, thelocalized position of a sound source may be calculated in up-downdirection. Specifically, in another embodiment, the localized positionof a sound source may be three-dimensionally calculated based on alocation relationship between the sound source and the localizationcalculation microphone 61 in the virtual three-dimensional space. Inthis case, a sound may be reproduced based on the calculated localizedposition of the sound source in an environment in which a loudspeaker(s)is provided in a real space in an up-down direction (e.g., 7.1 channelsurround sound).

In the above embodiment, the volume of a sound of a sound source variesdepending on the distance from the sound source, and the volume is thesame on a circle having a predetermined radius with the center of thecircle located at the sound source. In another embodiment, the volume ofa sound source may vary depending on the distance from the sound sourceand the direction of the sound source.

In the above embodiment, a low-pass filter is used as a frequency filterto reduce the volumes of components higher than or equal to apredetermined frequency, thereby correcting a sound. In anotherembodiment, a band-pass filter, a high-pass filter, or aband-elimination filter may be used as a frequency filter to correct asound. In another embodiment, a sound may be corrected as follows: afrequency filter may be used to increase the volumes of components lowerthan or equal to (higher than or equal to or within a predeterminedrange of) a predetermined frequency, thereby relatively decreasingcomponents higher than or equal to a predetermined frequency.

In another embodiment, in addition to the frequency filter, a techniquefor changing specific frequency characteristics (e.g., an equalizer), amultiband compressor, an effector, etc., may be used to correct a sound.

The above audio process may be performed on any other sounds (e.g., thevoice of a predetermined character, etc.).

In the above embodiment, a sound of a sound source located behind thevirtual camera 60 is corrected using a frequency filter. In anotherembodiment, a sound of a sound source in a predetermined direction (afront direction, a right direction, etc.) as viewed from the virtualcamera 60 may be corrected using a frequency filter. In still anotherembodiment, a sound of a sound source in a predetermined direction (afront direction, a right direction, etc.) as viewed from a playercharacter, instead of a predetermined direction as viewed from thevirtual camera 60, may be corrected using a frequency filter.Specifically, a direction of a sound source as viewed from a virtualcamera or a predetermined character in the virtual space (a direction ofthe sound source with reference to the virtual camera or thepredetermined character) may be calculated, and if the calculateddirection is a predetermined direction, the sound of the sound sourcemay be corrected.

The above audio process (the process using a plurality of microphonesand the process using a filter) is not limited to the above game, andmay be performed in any other games. The above audio process is also notlimited to games, and may be performed in specific simulation systems.

In this embodiment, the game program is executed by the game device 3.In another embodiment, the game program may be executed in a generalinformation processing device (a personal computer, a smartphone, etc.)in addition to a game-specialized device. Specifically, in anotherembodiment, a general information processing device may function as agame device by executing the game program.

The game program may be stored in a storage medium such as a magneticdisk, a non-volatile memory, etc., in addition to an optical disc. Thegame program may be stored in a computer-readable storage medium such asa RAM, a magnetic disk, etc., on a server connected to a network, andmay be provided via the network. The game program may be read as asource code into an information processing device, and may be compiledand executed when the program is executed.

In the above embodiment, the process of the flowchart is performed bythe CPU 10 of the game device 3 executing the game program. In anotherembodiment, a portion of or the entire process may be performed using adedicated circuit included in the game device 3 or a general-purposeprocessor. At least one processor may operate as a “programmed logiccircuit” for executing the process.

In another embodiment, in an information processing system having aplurality of information processing devices which can communicate witheach other, the plurality of information processing devices may sharethe load of the game process executed by the game device 3. For example,the game system may include a plurality of information processingdevices connected to a network such as the Internet. Specifically, forexample, a server on the network may perform a process instead of thegame device 3. Thereafter, a terminal on the network may receive theprocess result from the server, a game image may be displayed on adisplay device connected to the terminal, and a game sound may be outputfrom a loudspeaker connected to the terminal.

While certain example systems, methods, devices and apparatuses havebeen described herein, it is to be understood that the appended claimsare not to be limited to the systems, methods, devices and apparatusesdisclosed, but on the contrary, are intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A non-transitory computer-readable storage mediumstoring an information processing program executable by a computer of aninformation processing device for generating an image of a virtual spacecaptured by a virtual camera and outputting a sound of a sound sourceprovided in the virtual space, the program, when executed, causing thecomputer to perform: calculating a direction of the sound source asviewed from the virtual camera or a predetermined character provided inthe virtual space; calculating an angle between an imaging direction ofthe virtual camera or a direction measured with reference to thepredetermined character and the direction of the sound source;correcting the sound of the sound source by applying a predeterminedfilter to the sound when the calculated direction of the sound sourcecorresponds to a predetermined direction as viewed from the virtualcamera or the predetermined character provided in the virtual space; andoutputting the corrected sound, wherein when the calculated angle isgreater than a first threshold value, the sound is corrected.
 2. Anon-transitory computer-readable storage medium storing an informationprocessing program executable by a computer of an information processingdevice for generating an image of a virtual space captured by a virtualcamera and outputting a sound of a sound source provided in the virtualspace, the program, when executed, causing the computer to perform:calculating a direction of the sound source as viewed from the virtualcamera or a predetermined character provided in the virtual space;calculating an angle between an imaging direction of the virtual cameraor a direction measured with reference to the predetermined characterand the direction of the sound source; correcting the sound of the soundsource by applying a predetermined filter to the sound when thecalculated direction of the sound source corresponds to a predetermineddirection as viewed from the virtual camera or the predeterminedcharacter provided in the virtual space; and outputting the correctedsound, wherein a degree of correction of the sound is increased with anincrease in the calculated angle.
 3. The non-transitorycomputer-readable storage medium of claim 1, wherein when the soundsource is located behind the virtual camera or the predeterminedcharacter, the sound is corrected.
 4. The non-transitorycomputer-readable storage medium of claim 1, wherein the sound is alsocorrected based on a distance between the virtual camera or thepredetermined character and the sound source.
 5. The non-transitorycomputer-readable storage medium of claim 4, wherein when the distancebetween the virtual camera or the predetermined character and the soundsource is larger than a second threshold value, the sound is corrected.6. The non-transitory computer-readable storage medium of claim 4,wherein a degree of correction of the sound is increased with anincrease in the distance.
 7. The non-transitory computer-readablestorage medium of claim 2, wherein the degree of correction of the soundis increased by increasing a degree of attenuation of a volume of apredetermined frequency component of the sound.
 8. The non-transitorycomputer-readable storage medium of claim 1, wherein the sound iscorrected by attenuating a predetermined frequency component of thesound.
 9. The non-transitory computer-readable storage medium of claim1, wherein the program causes the computer to further execute:determining whether or not to correct the sound, based on a type of thesound source or a type of the sound of the sound source, and when it isdetermined that the sound is to be corrected, the sound is corrected.10. The non-transitory computer-readable storage medium of claim 1,wherein a degree of correction of the sound is set based on a type ofthe sound source or a type of the sound of the sound source, and thesound is corrected to the degree of correction.
 11. The non-transitorycomputer-readable storage medium of claim 1, wherein the predeterminedfilter is a frequency filter.
 12. The non-transitory computer-readablestorage medium of claim 11, wherein the frequency filter is at least oneof a low-pass filter and a band-pass filter.
 13. A non-transitorycomputer-readable storage medium storing an information processingprogram executable by a computer of an information processing device forgenerating an image of a virtual space captured by a virtual camera andoutputting a sound of a sound source provided in the virtual space, theprogram, when executed, causing the computer to perform: calculating adirection of the sound source as viewed from the virtual camera or apredetermined character provided in the virtual space; calculating anangle between an imaging direction of the virtual camera or a directionmeasured with reference to the predetermined character and the directionof the sound source; correcting the sound of the sound source byapplying a predetermined filter to the sound when the calculateddirection of the sound source corresponds to a predetermined directionas viewed from the virtual camera or the predetermined characterprovided in the virtual space; and outputting the corrected sound,wherein an angle between an imaging direction of the virtual camera or adirection measured with reference to the predetermined character and thedirection of the sound source is calculated, a maximum value of a degreeof correction is set based on the angle, the degree of correction isdetermined within the maximum value based on a distance between thevirtual camera or the predetermined character and the sound source, andthe sound is corrected based on the degree of correction.
 14. Aninformation processing device for generating an image of a virtual spacecaptured by a virtual camera and outputting a sound of a sound sourceprovided in the virtual space, comprising: a computer processing system,including at least one computer processor, the computer processingsystem being configured to: calculate a direction of the sound source asviewed from the virtual camera or a predetermined character provided inthe virtual space; calculate an angle between an imaging direction ofthe virtual camera or a direction measured with reference to thepredetermined character and the direction of the sound source; correctthe sound of the sound source by applying a predetermined filter to thesound when the calculated direction of the sound source corresponds to apredetermined direction as viewed from the virtual camera or thepredetermined character provided in the virtual space; and output thecorrected sound, wherein when the calculated angle is greater than afirst threshold value, the sound is corrected.
 15. An informationprocessing system for generating an image of a virtual space captured bya virtual camera and outputting a sound of a sound source provided inthe virtual space, comprising: a computer processing system, includingat least one computer processor, the computer processing system beingconfigured to: calculate a direction of the sound source as viewed fromthe virtual camera or a predetermined character provided in the virtualspace; calculate an angle between an imaging direction of the virtualcamera or a direction measured with reference to the predeterminedcharacter and the direction of the sound source; and correct the soundof the sound source by applying a predetermined filter to the sound whenthe calculated direction of the sound source corresponds to apredetermined direction as viewed from the virtual camera or thepredetermined character provided in the virtual space; and a soundoutput device configured to output the corrected sound, wherein when thecalculated angle is greater than a first threshold value, the sound iscorrected.
 16. An information processing method executed by a computerin an information processing system for generating an image of a virtualspace captured by a virtual camera and outputting a sound of a soundsource provided in the virtual space, the method comprising: calculatinga direction of the sound source as viewed from the virtual camera or apredetermined character provided in the virtual space; calculating anangle between an imaging direction of the virtual camera or a directionmeasured with reference to the predetermined character and the directionof the sound source; correcting the sound of the sound source byapplying a predetermined filter to the sound when the calculateddirection of the sound source corresponds to a predetermined directionas viewed from the virtual camera or the predetermined characterprovided in the virtual space; and outputting the corrected sound,wherein when the calculated angle is greater than a first thresholdvalue, the sound is corrected.
 17. A non-transitory computer-readablestorage medium storing an information processing program executable by acomputer of an information processing device, the program causing thecomputer to execute: generating an image of a virtual space captured bya virtual camera, the virtual space including a sound source;calculating a direction of the sound source as viewed from the virtualcamera in the virtual space; calculating an angle between an imagingdirection of the virtual camera and the calculated direction of thesound source as viewed from the virtual camera in the virtual space;correcting the sound of the sound source by applying a predeterminedfilter to the sound when the calculated direction of the sound sourcecorresponds to a predetermined direction as viewed from the virtualcamera in the virtual space, wherein a degree of correction of the soundis increased with an increase in the calculated angle; and outputtingthe corrected sound.
 18. The non-transitory computer-readable storagemedium of claim 17, wherein the predetermined filter attenuates apredetermined frequency component of the sound.
 19. The non-transitorycomputer-readable storage medium of claim 17, wherein the sound iscorrected based on a distance between the sound source and a referencepoint which is different from the virtual camera.
 20. An informationprocessing device for generating an image of a virtual space captured bya virtual camera and outputting a sound of a sound source provided inthe virtual space, comprising: a computer processing system, includingat least one computer processor, the computer processing system beingconfigured to: calculate a direction of the sound source as viewed fromthe virtual camera or a predetermined character provided in the virtualspace; calculate an angle between an imaging direction of the virtualcamera or a direction measured with reference to the predeterminedcharacter and the direction of the sound source; correct the sound ofthe sound source by applying a predetermined filter to the sound whenthe calculated direction of the sound source corresponds to apredetermined direction as viewed from the virtual camera or thepredetermined character provided in the virtual space; and output thecorrected sound, wherein a degree of correction of the sound isincreased with an increase in the calculated angle.
 21. An informationprocessing system for generating an image of a virtual space captured bya virtual camera and outputting a sound of a sound source provided inthe virtual space, comprising: a computer processing system, includingat least one computer processor, the computer processing system beingconfigured to: calculate a direction of the sound source as viewed fromthe virtual camera or a predetermined character provided in the virtualspace; calculate an angle between an imaging direction of the virtualcamera or a direction measured with reference to the predeterminedcharacter and the direction of the sound source; and correct the soundof the sound source by applying a predetermined filter to the sound whenthe calculated direction of the sound source corresponds to apredetermined direction as viewed from the virtual camera or thepredetermined character provided in the virtual space; and a soundoutput device configured to output the corrected sound, wherein a degreeof correction of the sound is increased with an increase in thecalculated angle.
 22. An information processing method executed by acomputer in an information processing system for generating an image ofa virtual space captured by a virtual camera and outputting a sound of asound source provided in the virtual space, the method comprising:calculating a direction of the sound source as viewed from the virtualcamera or a predetermined character provided in the virtual space;calculating an angle between an imaging direction of the virtual cameraor a direction measured with reference to the predetermined characterand the direction of the sound source; correcting the sound of the soundsource by applying a predetermined filter to the sound when thecalculated direction of the sound source corresponds to a predetermineddirection as viewed from the virtual camera or the predeterminedcharacter provided in the virtual space; and outputting the correctedsound, wherein a degree of correction of the sound is increased with anincrease in the calculated angle.
 23. An information processing devicefor generating an image of a virtual space captured by a virtual cameraand outputting a sound of a sound source provided in the virtual space,comprising: a computer processing system, including at least onecomputer processor, the computer processing system being configured to:calculate a direction of the sound source as viewed from the virtualcamera or a predetermined character provided in the virtual space;calculate an angle between an imaging direction of the virtual camera ora direction measured with reference to the predetermined character andthe direction of the sound source; correct the sound of the sound sourceby applying a predetermined filter to the sound when the calculateddirection of the sound source corresponds to a predetermined directionas viewed from the virtual camera or the predetermined characterprovided in the virtual space; and output the corrected sound, wherein amaximum value of a degree of correction is set based on the angle, thedegree of correction is determined within the maximum value based on adistance between the virtual camera or the predetermined character andthe sound source, and the sound is corrected based on the degree ofcorrection.
 24. An information processing system for generating an imageof a virtual space captured by a virtual camera and outputting a soundof a sound source provided in the virtual space, comprising: a computerprocessing system, including at least one computer processor, thecomputer processing system being configured to: calculate a direction ofthe sound source as viewed from the virtual camera or a predeterminedcharacter provided in the virtual space; calculate an angle between animaging direction of the virtual camera or a direction measured withreference to the predetermined character and the direction of the soundsource; and correct the sound of the sound source by applying apredetermined filter to the sound when the calculated direction of thesound source corresponds to a predetermined direction as viewed from thevirtual camera or the predetermined character provided in the virtualspace; and a sound output device configured to output the correctedsound, wherein a maximum value of a degree of correction is set based onthe angle, the degree of correction is determined within the maximumvalue based on a distance between the virtual camera or thepredetermined character and the sound source, and the sound is correctedbased on the degree of correction.
 25. An information processing methodexecuted by a computer in an information processing system forgenerating an image of a virtual space captured by a virtual camera andoutputting a sound of a sound source provided in the virtual space, themethod comprising: calculating a direction of the sound source as viewedfrom the virtual camera or a predetermined character provided in thevirtual space; calculating an angle between an imaging direction of thevirtual camera or a direction measured with reference to thepredetermined character and the direction of the sound source;correcting the sound of the sound source by applying a predeterminedfilter to the sound when the calculated direction of the sound sourcecorresponds to a predetermined direction as viewed from the virtualcamera or the predetermined character provided in the virtual space; andoutputting the corrected sound, wherein a maximum value of a degree ofcorrection is set based on the angle, the degree of correction isdetermined within the maximum value based on a distance between thevirtual camera or the predetermined character and the sound source, andthe sound is corrected based on the degree of correction.